Researchers from the United States and Norway conducted an observational study involving a 20-year cohort of young adults from the Coronary Artery Risk Development in Young Adults (CARDIA) study. Participants were assigned to 1 of 2 groups based on their self-reported overall eating habits. Those in the “prudent” group reported higher intakes of fruit, whole grains, milk, nuts, and seeds; the “Western” group reported eating more fast food, meat, poultry, pizza, and snacks.

Not surprisingly, prudent eaters had a lower risk of incident metabolic syndrome and each of its components than Western eaters. Further, those who didn’t drink diet beverages also had a lower risk of incident metabolic syndrome than those who did, but associations between diet beverage consumption with the components of cardiometabolic syndrome were variable and less clear.

Generally speaking, prudent eaters were more likely than Western eaters to consume low-calorie beverages. In fact, 66% of diet-beverage drinkers ate a prudent diet; however, prudent eaters who didn’t drink diet beverages had the lowest risk for high waist circumference, high triglycerides, and cardiometabolic syndrome.

The authors concluded that a prudent diet is consistently associated with lower risk of cardiometabolic disorder, and that not consuming diet beverages sometimes, but not always, lowers that risk a bit more.

A limitation of the study is that it was not designed to determine cause and effect, the authors acknowledge in The American Journal of Clinical Nutrition (2012;95[4]:909-915). In addition, although they followed participants for more than 20 years, diet was evaluated at the beginning of the study, and eating habits can change over time. Finally, self-reports are often unreliable and are prone to under- or overreporting.